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Thread: CYA Fell 20

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    Join Date
    May 2015
    Location
    Miami, Fl
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    47

    CYA Fell 20

    I had a large bather load yesterday. Before the swim, I brought FC from 8.5 to 9. I added another 25oz afterwards to raise it another 1ppm per pool math. This morning I noticed it was cloudy and smelled funny, don't know if was ammonia or not. FC was at 7.5. I just checked CYA and it was at 50, checked it twice. Last 2 checks were steady at 70, last one 4 days ago. FC now at 6.5. Any thoughts?
    Built March 2015 13000 gallon free form exposed aggregate with sheer descent, Jandy 2HP VSP, Jandy 1400 SWG with Aqualink PDA and AquaCal electrical heater. Pentair Clean and Clear filter 150SF. TF100 test kit. Pentair Kreepy Krualy Great White.

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    Join Date
    Mar 2007
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    San Rafael, CA USA
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    12,082

    Re: CYA Fell 20

    Unlikely to have dropped that fast without water dilution and with chlorine in the water (so bacteria couldn't grow). Perhaps your lighting conditions changed? Are you viewing the tube with your back to the sun so that your body is shading it and you look straight down into it?
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    May 2015
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    Miami, Fl
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    Re: CYA Fell 20

    Holding it at waist level, same location inside the house with no lighting as always. Might add that after adding the chlorine last night the pump turned off as it was scheduled to do so. I will recheck tomorrow morning again before adding any CYA.

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    Mar 2007
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    San Rafael, CA USA
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    Re: CYA Fell 20

    So usually indoor lighting is not nearly bright enough so generally your readings indoors will have the test read a CYA that is higher than it actually is. Try standing outside with your back to the sun and you shading the tube in front of you. That is strong indirect light that is how the test is designed/calibrated.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Join Date
    May 2015
    Location
    Miami, Fl
    Posts
    47

    Re: CYA Fell 20

    Will do chemgeek. Will try in the morning at your suggestion and re post. Thank you much.

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